Centrifuge 3 30 k

The viable cell concentration indicating the amount of viable cells in the cultivation and the viability of cells according to the total cell concentration, as well as the average cell diameter, were analyzed with the Trypan Blue Assay based Cedex HiRes Cell Counter and Analyzer system (Roche). The pH and the glucose concentration were measured offline in a blood gas analyzer (ABL800 Basic, Radiometer).
For the WCW measurement, 5 mL of the cell broth was transferred into a 15 mL Falcon^® tube (Sarstedt). The cell suspension was centrifuged (Centrifuge 3–30 K, Sigma) at 5000g at room temperature for 5 min. After centrifugation the media was removed and the pellet was weighed (Genius, Sartorius AG). The WCW was calculated according to Eq. 3, with w_Pellet indicating the weight of the tube together with the pellet and w_Tube, the empty weight of the falcon before adding the cell suspension. The sample volume described the amount of cell broth that was added to each tube before centrifugation. $$\mathrm{W}\mathrm{C}\mathrm{W}=\frac{{(w}_{\mathrm{P}\mathrm{e}\mathrm{l}\mathrm{l}\mathrm{e}\mathrm{t}}-w_{\mathrm{T}\mathrm{u}\mathrm{b}\mathrm{e})}}{\mathrm{S}\mathrm{a}\mathrm{m}\mathrm{p}\mathrm{l}\mathrm{e}\mathrm{v}\mathrm{o}\mathrm{l}\mathrm{u}\mathrm{m}\mathrm{e}}$$
The VCV was calculated based on the offline VCC, the diameter measured in the Cedex and the equation of a sphere indicating the cell shape according to: $$\mathrm{V}\mathrm{C}\mathrm{V}=\frac{4}{3}\pi {\left(\frac{\mathrm{C}\mathrm{e}\mathrm{l}\mathrm{l}\mathrm{d}\mathrm{i}\mathrm{a}\mathrm{m}\mathrm{e}\mathrm{t}\mathrm{e}\mathrm{r}}{2}\right)}^3\times \mathrm{V}\mathrm{C}\mathrm{C}$$